Mounting vacuum bulbs



Feb. 1 1927. 1,615,983

- c. G 'JONES MOUNTING vacuum BULBS Original Filed July 15, 1 921 Patented at. 1,1927.

UNITED STATES 1,615,98 ,PATENT OFFICE;

CHARLES G. JONES, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY,

INCORPORATED, OF NEW YORK, N.

Y., A CORPORATION OF rmwxonx.

5 MOUNTING VACUUM BULBS,-

' Application filed July 15, 1921,8eria1 No. 484,855. Renewed May 1, 1925.

This inveutionvrelates to the mounting of vacuum bulbs and especially to the mounting of vacuum thermo-couple bulbs.

The invention aims to protect vacuum bulbs from extraneous influences in the nature of either mechanical shocks or thermal effects or both, and at the same time to provide for readily replacing the bulbs, and for readily connecting them in electric circuits. I i

This is done by surrounding the thermocou'ple bulb with heat insulating and shock absorbing material,- such as cotton batting or the like. The bulb and the protective covering are inclosed in a cylindrical metal casing open at one end, arid a plug of insulating material is provided for closing this end of-the cylinder and for carrying electrical terminals for the vacuum bulb. The plug is detachably fastened in the casing by screws or the like in such a manner that it may readily be withdrawn from the casing for renewal of the vacuum bulb. Means is provided extending inwardly and laterally of the casing for limiting the movement of said plug into and axially of said casing, but permitting free outward movement of the plug. In the preferred form of the invention, the end of the casing adjacent the plug is provided with a lug for engaging a bayonet slot in the socket in which the casing is adapted to fit.

In the acoompanylng drawings, Fig. 1 isa perspective view, partly in section, of one embodiment of the invention, and Fig. 2 is a similar view of the preferred form of the invention. I

In Fig. 1 a vacuum thermo-couple bulb of 'a type well known in the art is shown at 1. This bulb comprisesan evacuated envelope 2, preferably of glass, which contains the thermo-couple element proper consisting of two wires 3 and 4 of dissimilar materials, and which also contains the heater element 5 adapted to be heated by the passage therethrough of an electric current, as for instance, a current to be measured or a known fraction of the current to be measured.

When the bulb is in use the heater member heats the thermo-junction, which is attached tothe middle point of the heater element, and the electromotive force generated by the thermo-couple isapplied to a sensitive galvanometer (not shown) connected to the terminals of the thermo-couple, the galvanometer thus serving to indicate the heat developed and therefore the current passin through the heater element.

Since this i-nvention'is not concerned with the specific form of the thermo-couple bulb and the operation of such devices is well understood by those skilled in the art, the operation of the thermo-couple bulb and the specific form of the bulb are not further considered herein. A similar thermo-couple bulb is disclosed in Patent No. 1,426,861 of August 22, 1922, entitled Measuring devices, assigned to the assignee of this application.

A cylindrical metallic casing 6, comprising a tubular portion 7 and an end plate 8 i is provided for inclosing thevbulb 1. This plate 8 is rigidly attached to the tubular portion 7 in any suitable Way, as by soldermg 9 with holes 10 therein, the lugs fitting in notches 1.1 in the end of the tubular portion 7 and being designed to receive screws or other fastening means (not shown) for securing the casing 6 to a base or support (not shown) of any suitable type. The end of the casing 6 remote from plate 8 is open, and a plug 12 of insulating material is pro vided for closing this opening. -Heat insulating and shock absorbing material 22, such as cotton batting or the like, completely envelops the bulb 1 and spaces it from the cas ing 6 and plug 12. The stem end 23 ofthe envelope 2 is supported by material 22, thereby difi'erentiating from prior arrangements whereby the stem end of the envelope was rigidly held in sealing wax or the like. Due to'its heat insulating properties this-material 22 protects the therrno-couple against appreciable error due to ordinary sources of external heat and due to the shock a orbor welding. The plate 7 has two lugs ing properties of this material the bulb is snugly in casing 6, and the studs 13 fitting snugly in the plug 12 completely close the openings through the plug. The plug 12 is det-achably fastened in the casing 6by screws 17. By simply removing the screws the plug 12 and bulb 1 may be withdrawn from the casing 6 so that the bulb may be readily replaced by another bulb in case a change of bulbs is desirable or necessary. The tubular wall 7 is provided with countersunk or inwardly projecting portions as at 18 to permit the heads of Screws 17 to lie within the cylinder formed by the outer surface of the tubular wall 7, and the plug 12 is provided with slots 19 for receiving the countersunk or' inwardly projecting portions 18. The slots 19 extend from the inner face of the plug 12 to just past the portions 18, so that the shoulders 20 formed by the closed ends of the slots will abut against the portions 18 and thus limit the movement of plug 12 into zthe casing 6.. The side walls of the slots 19 assist the screws 17 in preventing thev plug 12 from twisting or turnmg'in its plane in the casing 6. The casing 6 is preferably of brass and is preferably nickel plated and highly polished outside, so that it will, as far as possible, reflect incident heat rays The plug 12 fits entirely within the casing 6, so that the plug is properly protected against chipping or breaking.

Fig. 2 shows a vacuum thermo-couple similar to that of Fig. 1 except that the easing 6 of Fig. 2, corresponding to the casing 6 of Fig. 1, is provided with :1 lug 21 and that the outer ends of terminal lugs 13', corresponding to the terminal lugs 13 of Fig. 1 are formed for properly cooperating with the terminal in a socket of the type, for instance, shown in U. S. patent to Shreeve, 1,325,865, Dec. 23, 1919, entitled Vacuum tube socket, and that the ears 9, corresponding to elements 9 of Fig. 1 merely extend to the outer surface of the tubular portion of casing 6'. The lug 2,1 is adapted to cooperate with a bayonet slot in the socket in 'which the casing 6 is adapted to fit, in order toretain the thermo-couple in the socket. The various parts of the thermocouple of Fig. 2 are numbered like the corresponding parts of the device shown n F g. 1, except that the reference numbers 1n Fig. 2 are primed.

What is claimed is:

1. A vacuum tube mountin comprising a casing for inclosing said" we, said cas ng being 0 en at one end, a plug of insulating materia for closing'said end of. said casing,

said plug carrying electrical, terminals .for

said tube, and means extending inwardly from and laterally of said casing for limit ing the movement of said plug into and axially of said casing, but permitting free outward movement of said plug at all times.

2. A vacuum tube mounting comprising a cylindrical casing for inclosing said vacuum tube, said casing being open at one end,

a plug of insulating material for closing said end of said casing, said plug carrying electrical terminals for said vacuum tube, and means for detachably securing said plug in said end of said casing, said means lying entirely within the cylinder formed by the outer surface of said casing, whereby said end of saidcasin is adapted to be fitted into a cylindrical soc ret.

3. A vacuum tube mounting comprising a casing for-inclosing said vacuum tube, said casing being open at one end, a plug of insulating material for closing said end of said casing, said plug carrying electrical terminals for said vacuum tube and'fitting entirely within said casing, and means for detachably securing said plug in said casing, whereby said vacuum tube may be readily replaced.

4. A vacuum thermo-couple tube, a casing for inclosing said tube, said casing being open at one end, a plug of insulating mate- 'rial for closing said end of said casing, heat insulating and shock absorbing material surrounding said tube and supporting said tube in said casing, terminal studs for said tube mounted in. and extending through said plug, and electrical connections from the inner ends of said studs to said tube.

5. A vacuum tube mounting comprising a v casing for inclosing said tube, said casing being openat one end, a plug for closing said. end of said casing, said plug carrying electrical terminals for said tube, screws passing through said casing and into said plug for fastening said plug in said casing, said casing having portions countersunk to receive the heads of said screws, and a lug projecting from said casing adjacent said end of said casing, for cooperating with a bayonet slot of asocket adapted to receive said end of said casing, said plug having in its periphery slots, axial of said casing, extending from the inner side of said plug to points adjacent said screws, and the closed ends of said slots engaging said countersunk portions of said casing to limit the movement of said plug inwardly of said casing.

In witness whereof, I hereunto subscribe CHARLES e. JONES. 

